- For Part III only: Participant is a nursing mother, has difficulty distinguishing his/her migraine attacks from tension or interval headaches, has a history of predominantly mild migraine attacks or migraines usually resolved spontaneously in less than 4 hours, has basilar or hemiplegic migraine headache, has more than 15 headache-days per month or has taken medication for acute headache on more than 10 days per month in any of the 3 months prior to screening, is taking migraine prophylactic medication, was >50 years of at age of migraine onset, has, in the opinion of the investigator, other confounding pain syndromes, psychiatric conditions such as uncontrolled major depression, dementia or significant neurological disorders other than migraine, has liver function tests, specifically alanine aminotransferase (ALT)/aspartate aminotransferase (AST) and Alkaline Phosphatase are above the upper limit of normal at the prestudy (screening) visit or at recheck within 4 weeks prior to Day 1, is taking strong or moderate Cytochrome P450 3A4 (CYP3A4) inhibitors such as Ketoconazole, Diltiazem or Verapamil